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BlIP Minerals is a large, diversified, international mineral producer. This paper describes the company's operating strategy, and identifies the role of mineral processing in this strategy through three examples: the column flotation installation at Escondida in Chile, the leach-SX-electrowinning plant, proposed for Escondida, and the whole-ore roasting process being constructed for the Syama gold operation in Mali. It is concluded that the application of appropriate and sometimes novel mineral processing technologies can achieve significant benefits in reduced operating cost, improved product quality, and in some cases the exploitation of previously uneconomic deposits, thereby providing strategic advantages to the company.

Jan 1, 1993

By Kelly BJ, Smith GA

The recommendations of a recent American report on "Better contracting for Underground Construction" are considered in relation to Contracting practices on major Australian projects by representatives Of the "classical trilogy" - the Owner, Engineer and Contractor.

Jan 1, 1976

By A Coulson, J Hussey

Noranda Inc is a Canadian mining and metallurgical company with its activities managed through businesses in copper and recycling, zinc, aluminum, magnesium and various metals through its interest in Falconbridge Ltd. Noranda operates three base metal mines, three copper smelters, one copper refinery, one zinc refinery, one lead smelter and refinery, three copper recycling and sampling facilities seven aluminum producing facilities and one magnesium production facility in the construction stage. The mining side of Noranda has a strong history of open stope, cut and fill and shrinkage mining. The 1999 Noranda Annual Report lists a 206 million tonne resource located at Porphyry Mountain in GaspT, QuTbec. Mont Porphyre is a large tonnage, low-grade porphyry style Cu-Mo deposit that was discovered in 1994. It is located at a depth between 1.0 and 1.7 km below surface and characterised by a very competent rock mass. The Mont Porphyre resource is located adjacent to the town of Murdochville, close to NorandaÆs Mines GaspT operations. Mines GaspT closed its open pit and underground operations in 1999 after approximately 45 years of mining, but still operates a copper smelter near Murdochville. The low-grade and great depth of the Mont Porphyre resource suggested that mine design could not be based on the conventional Noranda open stoping mining practice. This paper will review NorandaÆs approach to evaluating the Mont Porphyre deposit. The approach included two definition diamond drilling campaigns, a review of current caving practice, an in-house scope study, a geotechnical logging program for diamond drill core and participation in an international study on cave mining. One interesting component of NorandaÆs approach was the scope study that involved a team of multi-disciplinary personnel drawn together for a short period of time. The objective of the scope study was to determine what conditions would be necessary to mine the deposit and to assess the merits of continuing with further exploration work. A review of current worldwide underground bulk mining practices, and in particular an evaluation of the applicability of caving mining methods, were key components of the scope study. The scope study team concluded that derivatives of caving could be applied to the mining of Mont Porphyre, but additional diamond drilling was recommended to further define the deposit and improve the level of geotechnical information. Following the recommendations of the scope study team, a diamond drilling campaign was completed during the summer and fall of 1997. The 1997 drilling campaign had two secondary objectives, in addition to the primary objective of defining the limits of the orebody. The first objective was to improve the level of geotechnical information available for the characterisation of primary block cave fragmentation. The second objective was to improve the delineation of a lower grade intrusive core. A geomechanical investigation was conducted and included particular emphasis on geotechnical data collection and analysis. A review of the actual data collection process, including several trials of different core orientation techniques, will be included in the discussion.

Jan 1, 2000

By Dight P. M, Dugan K. J

Design approaches for the artificial support of open pit walls have been reviewed and the main factors affecting support performance have been identified. An example of passive support in a potentially unstable pit wall has been used to demonstrate the importance of slope displacement as part of the support design process.

Jan 1, 1989

Capital expenditure on sampling and blending is often very difficult to justify. The costs are easy to estimate but the benefits likely to be obtained by constructing good sampling and blending facilities are generally difficult to estimate. For instance, improving blending of the ore feed to a smelter would improve throughput, yield and controllability ... but by how much? Similarly, better sampling would allow processing conditions to be dynamically adjusted and would improve extraction ... but by how much? Predicting benefits often requires the use of simulation models which carefully distinguish between true grades, predicted grades and observed grades. The parameters of these simulation models must often be estimated from rather inadequate information. These difficulties are illustrated using three scenarios.

Jan 1, 2005

Corrosion is a chemical or electro-chemical attack on a metal by the surrounding medium, and it can be stated in general terms that a non-corrodible metal possesses that property either because there is no chemical action between it and the medium, or because the medium reacts quickly with the metal to produce a thin protective coating.When iron or steel is attacked by dilute mineral acids, for example, the products of the reaction are soluble and the formation of a protective film cannot take place; on the other hand, rusting produces a porous film which flakes away and offers little protection to the underlying metal. However, when chromium is alloyed with iron, its resistance to corrosion is improved because the films produced on such alloys become more adherent and tenacious as the proportion of chromium is increased. Chromium is thus an essestial constituent of the corrosion- and heat-resisting steels.During the 40 years which have elapsed since their initial development, these alloys have made an important place for themselves in in<lustry and commerce, and it is the object of this paper to 'describe typical examples of the many types which are available; also, to give some indication of their particular properties, and applications in the mining industry.NOMENCLATUREVery few of the alloys which are about to be described can strictly be considered stainless, and most are not steels in the sense that they can he hardened by quenching from...

Jan 1, 1951

By M P. Sandy

Some Western Australian underground mines are challenged by very high stress gradients. This environment frequently results in poor induced ground conditions and damaging seismic activity. In some cases, rockbursting or squeezing ground has been observed as shallow as 250 m below surface. Very few mines operating at depths greater than 500 m experience no stress-related issues. As a general result of this difficult environment, there are a growing number of mines that are now challenged or have been closed by induced geotechnical problems. Often, the up-front savings or perceived advantage of an inappropriate mine plan may be entirely lost to the real cost of managing the hazards, or a write-down of reserves resulting from access difficulties will diminish the economic position of the mine. From an engineering perspective, it is best if stress-related hazards can be proactively minimised, because reactive measures offer less improvement in risk exposure. In this paper, some examples of sequencing techniques for managing difficult environments are contrasted with examples from mines where developing hazards have adversely affected production or the economic viability of the project.

Jan 1, 2003

Cerro Matoso (CMSA) in Colombia produces ferro-nickel from lateritic ore containing approximately three per cent nickel, using a Rotary Kiln - Electric Furnace (RKEF) process, in which the calcining of the mineral within the kiln is second in importance only to the smelting of the mineral in the Electrical Furnace. This article discusses the installation and operation of an expert system to control the kiln of CMSA. In the CMSA process, the run-of-mine ore is crushed, homogenised, dried and mixed with a small percentage of coal, before being heated up to 900¦C in a rotary kiln in the presence of natural gas mixed with air in a controlled proportion (air/gas constant ratio). The final objectives of the process are the following: ò To reduce to a minimum the iron and nickel oxides in order to convert these into metallic ions; this is a reduction process to facilitate largely the smelting in the electric furnace. Since the reduction is made with natural gas, it is much more economical than the subsequent complete reduction in the electric furnace, since electrical energy is much more expensive by unit of processed mineral. ò To heat the mineral as much as possible to facilitate the subsequent smelting. ò To eliminate totally the moisture content of the ore. An expert system with fuzzy logic was commissioned in 1994 for the control of the kiln and it has operated with good results ever since.

Jan 1, 1996

In presenting size analysis data, one has the choice of various graphical techniques; each no doubt has been developed to highlight a particular aspect of the data. A frequency size distribution plot is used quite extensively to illustrate the importance of the finer size particles in iron ore granulation. However, the basis for such a plot is often not appreciated. As a result, cases of incorrect use can be cited. The aim of this paper is to extend the work of Alien (1981) and to provide, using examples and figures, a basic understanding of the implications of the various size distributions. A simplified method of presenting sizing data on a linear scale graph paper is presented and recommended. This involves a simple construction of a histogram of mass fraction versus particle size (in geometric progression).

Jan 1, 1992

Anglo Platinum recognised with its expanded operations the need to change its evaluation strategy due to increased sample volumes and the pressure it created at laboratories. The sender/receiver analytical scenarios had to change in order to curb costs and to prevent substantial investments in new sampling and analytical facilities. Given the high cost associated with correct sampling systems and sampling protocols and the shortage of technical resources a strategy of single point sampling and analysis was introduced. The analysis was then done at an ISO17025 accredited laboratory with ten per cent checks, subjected to careful statistical scrutiny. Logistical problems increased with respect to weighbridge congestion, maintaining sampling quality, throughput of samples in the sample preparation areas, manual quality control systems in place, audit trails and analytical capacity throughout all operations. This required the expedited improvement of existing sampling practices and the development of new sampling methods and equipment. Anglo Platinum is classifying and standardising sampling equipment, sample preparation and analytical procedures for all process streams with the view to minimise overall uncertainties. Major investments were made into a customised LIMS and automated equipment for data management, reduction of manual transcription errors and streamlining of sample processing. Anglo Platinum is committed in rolling out the enhancements to all sites as priority dictates.

Jan 1, 2008

By Thompson P, Sharma Y

The paper describes the methodology and results from a study carried out by Telfer Gold Mine to optimise the materials and costs involved in construction of the pad for their dump leach operations. The investigation involved large-scale field testing of five different types of liner and a number of different cushion and drainage layer configurations. The aim was to identify the most cost effective construction methods to allow the final dump height to be increased from 45 in to 60 in without causing significant damage to the liner. The effects of dump height on permeability were also investigated. These methods are described and results presented. The findings indicated that modifications to the existing liner/cushion layer/drainage layer configuration used previously at Telfer would actually reduce overall construction costs rather than increase them despite an increase in overall dump height. Relative construction costs are presented.

Jan 1, 1994

By Longtin Z, Jin C, Zixin C

This paper proposes a new idea of disintegrating mode (division into simpler sub-problems) for complex problems, and based on -it, a study of the structure and the design of a knowledge base and inference engine for layout design of mineral concentrator expert systems. There is also a study of the formalisation method for describing the layout picture, and the work derived therefore found a formalisation method for expressing the knowledge and experience of layout design. There is also a study of the general characteristics of layout design knowledge.

Jan 1, 1993

By T Kang, V Sahajwalla, L Lu

During devolatilisation, physical behaviour of coals was investigated in horizontal electrically heated furnace with an inert gas atmosphere, and gasification rates of four coal chars and coke were measured thermogravimetrically in a carbon dioxide atmosphere at temperatures in the range 1100oC - 1500oC. The volume change of chars was also measured in horizontal electrically heated furnace at various temperatures. Both reactivity and the activation energy for the gasification of coal chars were found to be strongly influenced by pore structure and the carbonisation conditions employed during preparation. CO2 reactivity of chars increases with increasing reaction temperature, and particularly increases more rapidly over 1300¦C. CO2 reactivity of coke is lower than that of non-coking coal chars in the range of 1100¦C to 1500¦C. CO2 reactivity of chars with smaller pore area and bigger pore diameter is less than that of chars with bigger pore area and smaller pore diameter. During gasification, the volume of chars did not change significantly at the lower temperatures of 1100¦C and 1200¦C, but at the high temperatures, 1300¦C to 1500¦C, the volume of chars quickly decreased due to ash softening and melting. The CO2 reactivities of the chars are controlled by the mixed control of chemical reaction and pore diffusion in the temperature range 1100¦C to 1300¦C, and by bulk diffusion in the temperature range 1400¦C to 1500¦C.

Jan 1, 2000

Gold recovery by catalytic copper ammonium thiosulphate solution has been studied. Such a process strategy is very attractive for leaching certain difficult-to-treat ores and presents lessened lixiviant toxicity compared to cyanide. Newmont Gold Company has evaluated the ammonium thiosulphate heap leach process for gold recovery from low-grade carbonaceous sulphidic refractory ores following biooxidation. The ammonium thiosulphate leach process has been studied in laboratory, pilot plant and demonstration scale. Satisfactory test results support the continuation of process development. However, the thiosulphate leach chemistry was found to be very complex. Maximum control of the stability of the leaching system is a key factor for success, especially for the heap leach process. Important solution chemistry is discussed in this paper.

Jan 1, 1997

Through partnering with mining customers, DYNO has been able to develop some specific technologies that benefit blasting operations particularly in underground mining. Some of these areas are: 1. Cost allocation and product tracking systems; 2. Borehole video surveys of breakthrough blastholes; 3. Borehole video photography for logging VRM blastholes; 4. Toe-load uphole loading for sublevel cave mining operations; 5. 3D blast modelling for underground ring blasting. This paper outlines these developments in the context of a Canadian underground metalliferous mine.

Jan 1, 1995

By O Otgonbayar, B Bayarmaa, D Batbyamba, S Amar-Amgalan, K H. Natsagdorj, J Nomin-Erdene, B Boldkhuu, T S. Sainzaya

The Argyle deposit in the Kimberley region of Western Australia was the world’s largest accumulation of natural diamonds. Following its discovery in 1979, the mining of associated alluvial diamonds commenced in 1983, followed by the pipe in late 1985. Over the life of the mine to its closure in November 2020, Argyle produced approximately 900 million carats of diamonds. Argyle diamonds are distinctive in having a predominance of brown colours and rare highly-prized pink diamonds, which are a signature of the deposit. The 3D geological model developed from mining and deep drilling shows that Argyle is a composite pipe formed by the coalescence of several steep-sided diatremes, each with their own feeder zones at depth, that were erupted along a NNE-trending fault. The ~1.2 Ga Argyle pipe is comprised of diamondiferous olivine lamproite volcaniclastic rocks and intruded by sparse olivine lamproite dykes. The volcaniclastic rocks are predominantly comprised of unconsolidated quartz-rich lapilli and coarse ash deposits formed by numerous phreatomagmatic eruptions of olivine lamproite magma through Mesoproterozoic water-rich sands and silts. Post-emplacement deformation has tilted the orebody 30° to the north and regional strike-slip faulting has offset, segmented, and elongated the orebody. Recent significant modifications of the geological model resulted from underground block cave operations, producing several critical lessons learnt. Diamond grade and quality reconciliation issues warranted a geological investigation which resulted in the recognition of new volcaniclastic olivine lamproite domains with a broad range of diamond grades, including some very high-grade units. The new lamproite domains had a significant effect on the block cave mining and resultant recovery of diamonds. The new findings enable a more coherent and detailed geological understanding of the volcanic emplacement and paragenetic sequence of the Argyle AK1 pipe. Structural modelling of the deposit also played a major role in the block cave mining tonnage recoveries and daily operations. The re-examination of the geology of the Argyle pipe and the results of this new information reinforces the need for ongoing robust geological work both in the early stages of mining a deposit and continued during the life of the mine.

Mar 22, 2022

Brisbane based and listed on the ASX, Eastern Corp is pursuing the development of coal projects in New Zealand. There are various reasons why New Zealand coals are of interest û substantial resources, stable political/economic environment, close to Asian markets. In just over 12 months, Eastern has secured an operating coal mine (Cascade) and a prospective exploration area (Whareatea West), both on the Denniston plateau region, on the south islandÆs west coast. A key focus of activities is the development of relationships with key stakeholders and the promotion of the local economy.   Certain barriers may exist to the entrance by foreign companies into the New Zealand coal mining sector. These include geological challenges provided by the heavy faulting of the coals, port and rail infrastructure constraints, and the ægreenÆ factor.

Jan 1, 2005

By Amer S, Novais A. Q, Limpo Gil J

A proprietary hydrometallurgical ammonium chloride process for the recovery of not only zinc, but also copper, lead and silver from sulphidic zinc-rich concentrates has been developed at bench scale by CENIM and INETI (ex-LNET) as part of a research project supported by the Commission of the European Community (DGXII). This paper deals with the innovative chemical aspects applied to this chloride process and also with the more relevant data relating to mass balance, heat balance and process economics. Under mild temperature and oxygen pressure leaching conditions it is possible to extract practically all the zinc together with the other metals of interest and to precipitate simultaneously the solubilised iron fraction as goethite. The pH is kept close to neutrality in spite of the ammonia released in the leaching of the non-ferrous sulphides. A buffer effect is observed mostly due to the formation of zinc ammines which are very soluble in this medium. The zinc is further extracted by D2EHPA, the acidity being neutralised by the ammonia. Most of the ammonium chloride is naturally regenerated in this step. The zinc is recovered as zinc cathodes in a conventional sulphate electrowinning circuit. All the main raw material consumptions excluding the concentrate, such as oxygen, lime and ammonium chloride are linked to the sulphate formation in the leaching step which must be kept as low as possible by decreasing the reaction time under neutral conditions. The process analysis is complemented by the economic evaluation of a reference case. Difficulties encountered in finding a more convenient method of assessing the economics of the process in the absence of a reference price for a complex sulphide concentrate are examined and discussed. The reason why this analysis was performed with a much more optimistic metal prices scenario is also highlighted. The process economics are primarily dependent on the zinc market quotations and of course on the concentrate cost. Around 70 per cent of the total revenue is due to zinc sales. Assuming an internal rate of return of 17 per cent, the price of the concentrate can be as high as 255 $US/t for a plant capacity of 320 000 t/y (90 000 t/y of zinc).

Jan 1, 1993

By Adhikari G. R, Raju N. M

The breaking of rock by explosives occurs so rapidly that the details of the phenomenon cannot he observed by the unaided eye. High resolution cameras and VCRs offer a means of slowing down the blasting action. A high resolution super video camera with digital zoom and a variable shutter speed was imported and used for the first time in India as a tool for blast optimisation studies at Malanjkhand Copper Project. Slow motion play-back revealed that the gases vented out through the fissures. The crest moved prior to the lower portion of the bench when initiated with detonating cord. The delay timing between the rows was not enough to provide sufficient relief and rock movement. This inadequate delay timing resulted in flyrock from the back rows. Stemming ejection was observed from practically all the holes. The muck profile was not satisfactory. A trial was carried out using 450 ms in hole delays and 25 nis surface delays. The front row holes were drilled based on the observations made from the laser profiling survey system. The video of the monitored blast showed that the rock started moving prior to the stemming ejection. It could be clearly seen that the entire block was completely initiated through the surface delays before the onset of the burden movement, thus eliminating any chance of misfires. Viewing blasts in high quality slow motion was useful to arrive at modified design parameters, resulting in uniform fragment size distribution and controlled rock movement.

Jan 1, 1995

By T Nixon

A common problem for many mines is insufficient total primary airflow or insufficient airflow in the correct places as the mine changes over its life. This has a number of impacts on the business operation and may result in the need for a major and unexpected capital upgrade of the system, cancellation of a planned production increase, reduction in production targets, increased operating costs, failure to provide contracted metals to customers or acceptance of substandard conditions in the workplace. In some cases, it can even result in premature closure of the mine. In recent times, higher metal prices have given an expected economic boost to many mines, potentially prolonging their life but simultaneously requiring the mine to develop to deeper depths or requiring assets such as shafts and fans to have their service life extended. Insufficient primary airflow is a particular problem in deeper mines as the ventilation circuits become longer, more convoluted, have higher shock losses and the actual airflow requirements increase due to a combination of leakage, dispersion of the workings and the problems of managing the additional heat loads due to higher virgin rock temperatures and autocompression. This paper discusses the reasons why mines experience unexpected shortfalls in primary ventilation capacity with its associated impacts on metal targets, profits and frequently on the health, safety and morale of the workforce, as well as its productivity.

Jan 1, 2008